Polymer composition for the manufacture of thermoformed articles

ABSTRACT

This invention relates to a polymer composition that is particularly suitable for use in the manufacture of thermoformed articles, which can be biodegraded in industrial composting. This invention also relates to a process for the production of the said composition and articles obtained thereby.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Phase filing under 35 U.S.C. § 371 ofPCT/EP2016/068237 filed on Jul. 29, 2016; and this application claimspriority to application Ser. No. 10/201,5000040869 filed in Italy onJul. 31, 2015 under 35 U.S.C. § 119. The entire contents of eachapplication are hereby incorporated by reference.

This invention relates to a polymer composition that is particularlysuitable for use in the manufacture of articles moulded by means ofthermoforming, which can be biodegraded in industrial composting.

This invention also relates to a process for the production of the saidcomposition and articles obtained thereby.

As is known, the techniques of hot moulding plastics materials, such asthermoforming, mainly find application in the production of articleshaving a high resistance to deformation, such as for example,containers, tubs, plates or capsules for the dispensing of beverages,with walls having thicknesses typically greater than 200 microns.

Although the manufacture of articles with such great thicknesses ensuresthe necessary properties of resistance to deformation, it neverthelesscreates difficulties in ensuring that these articles, when are made withpolymers which are themselves biodegradable, have disintegratabilityproperties rendering them suitable in plants for industrial composting.

In view of the above it would be desiderable to have a compositioncapable of being transformed economically and productively intothermoformed articles, without adversely affecting compostability.

It has now surprisingly been discovered that it is possible to meet thisrequirement by means of a polymer composition for the production ofthermoformed articles comprising:

-   i) 20-60% by weight, preferably 30-50% by weight, with respect to    the sum of components i.-iv. of at least one polyester comprising:    -   a) a dicarboxylic component comprising, with respect to total        dicarboxylic component:        -   a1) 0-20% in moles, preferably 0-10% in moles, of units            deriving from at least one aromatic dicarboxylic acid,        -   a2) 80-100% in moles, preferably 90-100% in moles, of units            deriving from at least one saturated aliphatic dicarboxylic            acid,        -   a3) 0-5% in moles, preferably 0.1-1% in moles, more            preferably 0.2-0.7% in moles, of units deriving from at            least one unsaturated aliphatic dicarboxylic acid;    -   b) a diol component comprising, with respect to total diol        component:        -   b1) 95-100% in moles, preferably 97-100% in moles, of units            deriving from at least one saturated aliphatic diol;        -   b2) 0-5% in moles, preferably 0-3% in moles, of units            deriving from at least one unsaturated aliphatic diol;-   ii) 5-35% by weight, preferably 10-20% by weight, with respect to    the sum of components i.-iv., of at least one polyhydroxyalkanoate;-   iii) 0.01-5% by weight, preferably 0.02-3% by weight, with respect    to the sum of components i.-iv., of at least one hydrolysis    stabilizer comprising at least one compound having di- and/or    multiple functional groups comprising carbodiimide groups;-   iv) 5-50% by weight, preferably 10-40% by weight, with respect to    the sum of components i.-iv., of at least one filler agent.

With regard to the polyesters of the composition according to thisinvention, these comprise a dicarboxylic component which comprises, withrespect to total dicarboxylic component, 0-20% in moles, preferably0-10% in moles of units deriving from at least one aromatic dicarboxylicacid and 80-100% in moles, preferably 90-100% in moles of units derivingfrom at least one saturated aliphatic dicarboxylic acid and 0-5% inmoles, preferably 0.1-1% in moles, more preferably 0.2-0.7% in moles, ofunits deriving from at least one unsaturated aliphatic dicarboxylicacid.

The aromatic dicarboxylic acids are preferably selected from aromaticdicarboxylic acids of the phthalic acid type, preferably terephthalicacid or isophthalic acid, more preferably terephthalic acid, andheterocyclic dicarboxylic acids, preferably 2,5-furandicarboxylic acid,2,4-furandicarboxylic acid, 2,3-furandicarboxylic acid,3,4-furandicarboxylic acid, more preferably 2,5-furandicarboxylic acid,their esters, their salts and their mixtures. In a preferred embodimentthe said aromatic dicarboxylic acids comprise:

-   -   from 1 to 99% in moles, preferably from 5 to 95% and more        preferably from 10 to 80%, of terephthalic acid, its esters or        its salts;    -   from 99 to 1% in moles, preferably from 95 to 5% and more        preferably from 90 to 20%, of 2,5-furandicarboxylic acid, its        esters or its salts.

The saturated aliphatic dicarboxylic acids are preferably selected fromC₂-C₂₄, preferably C₄-C₁₃, more preferably C₄-C₁₁, saturateddicarboxylic acids their C₁-C₂₄, preferably C₁-C₄, alkyl esters, theirsalts and their mixtures.

Preferably, the saturated aliphatic dicarboxylic acids are selectedfrom: succinic acid, 2-ethylsuccinic acid, glutaric acid,2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, undecandioic acid, dodecandioic acid, brassylic acidand their C₁₋₂₄ alkyl esters.

In a preferred embodiment of this invention the saturated aliphaticdicarboxylic acids comprise mixtures comprising at least 50% in moles,preferably more than 60% in moles, more preferably more than 65% inmoles of succinic acid, adipic acid, azelaic acid, sebacic acid,brassylic acid, their C₁-C₂₄, preferably C₁-C₄, esters and theirmixtures.

The unsaturated aliphatic dicarboxylic acids are preferably selectedfrom itaconic acid, fumaric acid, 4-methylene-pimelic acid, 3,4-bis(methylene) nonandioic acid, 5-methylene-nonandioic acid, their C₁-C₂₄,preferably C₁-C₄, alkyl esters, their salts and their mixtures.

In a preferred embodiment of this invention, the unsaturated aliphaticdicarboxylic acids comprise mixtures comprising at least 50% in moles,preferably more than 60% in moles, more preferably more than 65% inmoles of itaconic acid, its C₁-C₂₄, preferably C₁-C₄ esters. Morepreferably, the unsaturated aliphatic dicarboxylic acids compriseitaconic acid.

The diol component of the polyesters of the composition according tothis invention comprises 95-100% in moles, preferably 97-100% in moles,of units deriving from at least one saturated aliphatic diol, withrespect to total diol component, and 0-5% in moles, preferably 0-3% inmoles, with respect to total diol component, of units deriving from atleast one unsaturated aliphatic diol.

In a preferred embodiment, the diol component of the polyesters of thecomposition according to this invention consists of saturated aliphaticdiols.

With regard to the saturated aliphatic diols, these are preferablyselected from 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol,1,4-butandiol, 1,5-pentandiol, 1,6-hexandiol, 1,7-heptandiol,1,8-octandiol, 1,9-nonandiol, 1,10-decandiol, 1,11-undecandiol,1,12-dodecandiol, 1,13-tridecandiol, 1,4-cyclohexandimethanel,neopentylglycol, 2-methyl-1,3-propandiol, dianhydrosorbitol,dianhydromannitol, dianhydroiditol, cyclohexandiol,cyclohexanmethandiol, dialkyleneglycols and polyalkylene glycols with amolecular weight of 100-4000, such as for example polyethylene glycol,polypropylene glycol and their mixtures. Preferably the diol componentcomprises at least 50% in moles of one or more diols selected from1,2-ethandiol, 1,3-propandiol, 1,4-butandiol. More preferably the diolcomponent comprises, or consists of, 1,4-butandiol.

With regard to the unsaturated aliphatic diols, these are preferablyselected from cis 2-buten-1,4-diol, trans 2-buten-1,4-diol,2-butyn-1,4-diol, cis 2-penten-1,5-diol, trans 2-penten-1,5-diol,2-pentyn-1,5-diol, cis 2-hexen-1,6-diol, trans 2-hexen-1,6-diol,2-hexyn-1,6-diol, cis 3-hexen-1,6-diol, trans 3-hexen-1,6-diol,3-hexyn-1,6-diol.

With regard to polyesters i. in the composition, these are preferablyselected from aliphatic polyesters (“AP”) and aliphatic-aromaticpolyesters (“AAPE”).

In the meaning of this invention, by aliphatic polyesters AP are meantpolyesters comprising a dicarboxylic component which consists, withrespect to the total moles of the dicarboxylic component, 95-100% inmoles of at least one saturated aliphatic dicarboxylic acid and 0-5% inmoles of at least one unsaturated aliphatic dicarboxylic acid and a diolcomponent comprising, with respect to the total moles of the diolcomponent, 95-100% in moles of units deriving from at least onesaturated aliphatic diol and 0-5% in moles of units deriving from atleast one unsaturated aliphatic diol.

By AAPE polyesters, in this invention are meant polyesters comprising adicarboxylic component which consists at least one aromatic dicarboxylicacid compound, at least one saturated aliphatic dicarboxylic acid and0-5% in moles, with respect to the total moles of the dicarboxyliccomponent, of at least one unsaturated aliphatic dicarboxylic acid and adiol component comprising, with respect to the total moles of the diolcomponent, 95-100% in moles of units deriving from at least onesaturated aliphatic diol and 0-5% in moles of units deriving from atleast one unsaturated aliphatic diol.

In the case of the AP aliphatic polyesters, those preferred arepolyesters in which the dicarboxylic component comprises units derivingfrom at least one C₂-C₂₄, preferably C₄-C₁₃, more preferably C₄-C₁₁saturated aliphatic dicarboxylic acid, their C₁-C₂₄, preferably C₁-C₄alkyl esters, their salts and their mixtures and a diol componentcomprising units deriving from at least one saturated aliphatic diol,preferably selected from 1,2-ethandiol, 1,2-propandiol, 1,3-propandiol,1,4-butandiol.

In a preferred embodiment of this invention, polyester i. of thecomposition comprises at least one aliphatic polyester (AP), preferablypoly(1,4-butylene succinate), poly(1,4-butylene adipate), poly(1,4-butylene azelate), poly(1,4-butylene sebacate), poly(1,4-butyleneadipate-co-1,4-butylene succinate), poly(1,4-butyleneazelate-co-1,4-butylene succinate), poly(1,4-butylenesebacate-co-1,4-butylene succinate), poly(1,4-butylenesuccinate-co-1,4-butylene adipate-co-1,4-butylene azelate). In aparticularly preferred embodiment the said aliphatic polyester ispoly(1,4-butylene succinate).

In a further preferred embodiment of this invention, the polyester ofthe composition comprises at least one aliphatic-aromatic polyester(AAPE), and is advantageously selected from:

-   -   (A) polyesters comprising repetitive units deriving from        aromatic dicarboxylic acids of the phthalic acid type,        preferably terephthalic acid, aliphatic dicarboxylic acids and        aliphatic diols (AAPE-A), characterised by an aromatic units        content of between 35 and 60% in moles, preferably between 40        and 55% in moles with respect to the total moles of the        dicarboxylic component. The AAPE-A polyesters are preferably        selected from: poly(1,4-butyleneadipate-co-1,4-butylene        terephthalate), poly(1,4-butylene sebacate-co-1,4-butylene        terephthalate), poly(1,4-butylene azelate-co-1,4-butylene        terephthalate), poly(1,4-butylene brassylate-co-1,4-butylene        terephthalate), poly(1,4-butylene succinate-co-1,4-butylene        terephthalate), poly(1,4-butylene adipate-co-1,4-butylene        sebacate-co-1,4-butylene terephthalate), poly(1,4-butylene        azelate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate),        poly(1,4-butylene adipate-co-1,4-butylene        azelate-co-1,4-butylene terephthalate), poly(1,4-butylene        succinate-co-1,4-butylene sebacate-co-1,4-butylene        terephthalate), poly(1,4-butylene adipate-co-1,4-butylene        succinate-co-1,4-butylene terephthalate). poly(1,4-butylene        azelate-co-1,4-butylene succinate-co-1,4-butylene        terephthalate).    -   (B) polyesters comprising repetitive units deriving from        heterocyclic dicarboxylic acids, preferably        2,5-furandicarboxylic acid, aliphatic dicarboxylic acids and        aliphatic diols (AAPE-B), characterised by an aromatic units        content of between 50 and 80% in moles, preferably of between 60        and 75% in moles with respect to the total moles of the        dicarboxylic component. The AAPE-B polyesters are preferably        selected from: poly(1,4-butylene adipate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        sebacate-co-1,4-butylene 2,5-furandicarboxylate),        poly(1,4-butylene azelate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        brassylate-co-1,4-butylene 2,5-furandicarboxylate),        poly(1,4-butylene succinate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        adipate-co-1,4-butylene sebacate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        azelate-co-1,4-butylene sebacate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        adipate-co-1,4-butylene azelate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        succinate-co-1,4-butylene sebacate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        adipate-co-1,4-butylene succinate-co-1,4-butylene        2,5-furandicarboxylate), poly(1,4-butylene        azelate-co-1,4-butylene succinate-co-1,4-butylene        2,5-furandicarboxylate).

In addition to the dicarboxylic component and the diol component, thepolyesters of the composition according to this invention preferablycomprise repetitive units deriving from at least one hydroxy acid in aquantity of between 0 and 49%, preferably between 0 and 30% in moleswith respect to the total moles of the dicarboxylic component. Examplesof convenient hydroxyacids are glycolic, hydroxybutyric, hydroxycaproic,hydroxyvaleric, 7-hydroxyheptanoic, 8-hydroxycaproic, 9-hydroxynonanoicand lactic acids or lactides. The hydroxyacids may be inserted in thechain as such or may also be first caused to react with diacids ordiols.

Long molecules with two functional groups including functional groupswhich are not in a terminal position may also be present in quantitiesof not more than 10% in moles with respect to the total moles of thedicarboxylic component. Examples are dimer acids, ricinoleic acid andacids incorporating epoxy functional groups and also polyoxyethyleneswith molecular weights of between 200 and 10000.

Diamines, aminoacids and aminoalcohols may also be present inpercentages up to 30% in moles with respect to the total moles of thedicarboxylic component.

During preparation of the polyesters of the composition according tothis invention, one or more molecules with multiple functional groups inquantities of between 0.1 and 3% in moles with respect to the totalmoles of the dicarboxylic component (as well as any hydroxyacids) mayalso advantageously be added in order to obtain branched products.Examples of these molecules are glycerol, pentaerythritol,trimethylolpropane, citric acid, dipentaerythritol, acid triglycerides,polyglycerols.

The molecular weight Mn of the polyesters of the composition accordingto this invention is preferably ≥20000, more preferably ≥40000. As faras the polydispersity index of the molecular weights Mw/Mn is concerned,this is instead preferably between 1.5 and 10, more preferably between1.6 and 5 and even more preferably between 1.8 and 2.7.

The molecular weights M_(n) and M_(w) may be measured by means of GelPermeation Chromatography (GPC). The determination may be performed withthe cromatography system maintained at 40° C., using a set of threecolumns in series (particle diameter 5 μm and porosities of 500 Å, 10000Å and 100000 Å) respectively, a refractive index detector, chloroform aseluent (flow 1 ml/min) and using polystyrene as the reference standard.

The terminal acid groups content of the polyesters of the compositionaccording to this invention is preferably between 30 and 160 meq/kg.

The terminal acid groups content may be measured in the following way:1.5-3 g of the polyester are placed in a 100 ml flask together with 60ml of chloroform. After the polyester has completely dissolved 25 ml of2-propanol are added and, immediately before the analysis, 1 ml ofdeionised water. The solution so obtained is titrated against apreviously standardised solution of NaOH in ethanol. An appropriateindicator, such as for example a glass electrode for acid-basetitrations in non-aqueous solvents, is used to determine the end pointof the titration. The terminal acid groups content is calculated on thebasis of the NaOH solution in ethanol consumed using the followingequation:

${{Terminal}\mspace{14mu}{acid}\mspace{14mu}{groups}\mspace{14mu}{{content}( {{meq}\;\text{/}{kg}\mspace{14mu}{polymer}} )}} = \frac{\lfloor {( {V_{eq} - V_{b}} ) \cdot T} \rfloor \cdot 1000}{P}$in which: V_(eq)=ml of NaOH in ethanol solution at the end point of thetitration of the sample;

-   -   V_(b)=ml of NaOH in ethanol solution required to achieve a        pH=9.5 during the blank titration;    -   T=concentration of the solution of NaOH in ethanol expressed in        moles/litre;    -   P=weight of the sample in grams.

Preferably the polyesters of the composition according to this inventionhave an inherent viscosity (measured with an Ubbelohde viscometer forsolutions in CHCl₃ of concentration 0.2 g/dl at 25° C.) of more than 0.3dl/g, preferably between 0.3 and 2 dl/g, more preferably between 0.4 and1.3 dl/g.

Preferably the polyesters of the composition according to this inventionare biodegradable. In the meaning of this invention, by biodegradablepolymers are meant polymers which are biodegradable according tostandard EN 13432.

The polyesters of the composition according to this invention may besynthesised by any of the processes known in the art. In particular theymay advantageously be obtained through a polycondensation reaction.

Advantageously the synthesis process may be performed in the presence ofa suitable catalyst. Among such suitable catalysts mention may by way ofexample be made of organometallic compounds of tin, for examplederivatives of stannoic acid, titanium compounds, for example orthobutyltitanate, aluminium compounds, for example Al-triisopropyl, compounds ofantimony and zinc and zirconium and mixtures thereof.

In order to ensure high properties of resistance to deformation for thethermoformed articles, the composition according to this inventioncomprises 5-35% by weight, preferably 10-20% by weight, with respect tothe sum of components i.-iv., of at least one polyhydroxyalkanoate(component ii.) preferably selected from the group comprising thepolyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate,polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate,polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate,polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate,polyhydroxybutyrate-octadecanoate, poly3-hydroxybutyrate-4-hydroxybutyrate.

Preferably the polyhydroxyalkanoate of the composition comprises atleast 80% by weight of one or more polyesters of lactic acid.

In a preferred embodiment, the polyesters of lactic acid are selectedfrom the group which comprises poly L lactic acid, poly D lactic acid,poly D-L lactic acid stereo complex, copolymers comprising more than 50%in moles of the said polyesters of lactic acid or their mixtures.

The polyesters of lactic acid containing at least 95% by weight ofrepetitive units deriving from L-lactic or D-lactic acid or theircombinations, with a molecular weight Mw of more than 50,000 and with ashear viscosity of between 50 and 500 Pa·s, preferably between 100 and300 Pa·s (measured according to standard ASTM D3835 at T=190° C., shearrate=1000 s⁻¹, D=1 mm, L/D=10), are particularly preferred.

In a particularly preferred embodiment of the invention, the polyesterof lactic acid comprises at least 95% by weight of units deriving fromL-lactic acid, ≤5% of repetitive units deriving from D-lactic acidhaving a melting point in the range 135-170° C., a glass transitiontemperature (Tg) in the range 55-65° C. and an MFR (measured accordingto standard ASTM-D1238 at 190° C. and 2.16 kg) in the range 1-50 g/10min. Commercial examples of polyesters of lactic acid having theseproperties are for example products of the Ingeo™ trade mark Biopolymer4043D, 3251D and 6202D.

The composition according to this invention comprises 0.01-5% by weight,preferably 0.02-3% by weight, more preferably 0.1-1% by weight, of atleast one hydrolysis stabilizer (component iii.) which improvesstability to hydrolysis and is selected from compounds having di- and/ormultiple functional groups incorporating carbodiimide.

The compounds having di- and multiple functional groups incorporatingcarbodiimide groups which are used in the composition according to thisinvention are preferably selected from poly(cyclooctylene carbodiimide),poly(1,4-dimethylenecyclohexylene carbodiimide),poly(dicyclohexylmethane carbodiimide), poly(cyclohexylenecarbodiimide), poly(ethylene carbodiimide), poly(butylene carbodiimide),poly(isobutylene carbodiimide), poly(nonylene carbodiimide),poly(dodecylene carbodiimide), poly(neopentylene carbodiimide),poly(1,4-dimethylene phenylene carbodiimide),poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide) (Stabaxol® D),poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide) (Stabaxol® P-100),poly(2,6 diisopropyl-1,3-phenylene carbodiimide) (Stabaxol® P), poly(tolyl carbodiimide), poly(4,4′-diphenylmethane carbodiimide),poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylene carbodiimide),poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylenecarbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide),p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide),1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylenebis(ethylcarbodiimide) and their mixtures.

The composition according to this invention comprises 5-50% by weight,preferably 10-40% by weight, of at least one filler agent (componentiv.) which helps to improve the resistance to deformation and thedimensional stability of the thermoformed objects according to thisinvention and is preferably selected from kaolin, barytes, clay, talc,carbonates of calcium and magnesium, iron and lead, aluminium hydroxide,diatomaceous earth, aluminium sulfate, barium sulfate, silica, mica,titanium dioxide, wollastonite, starch, chitin, chitosane, alginates,proteins such as glutine, zein, casein, collagen, gelatine, naturalrubbers, rosinic acid and their derivatives.

By the term starch are meant here all types of starch, that is: flour,native starch, hydrolysed starch, destructured starch, gelatinisedstarch, plasticised starch, thermoplastic starch, biofiller comprisingcomplexed starch or mixtures thereof. Particularly suitable according tothe invention are starches such as potato, maize, tapioca and peastarch.

Starches which are capable of being easily destructured and which havehigh initial molecular weights, such as for example potato starch andmaize starch, have proved to be particularly advantageous.

The starch may be present either as such or in chemically modified formsuch as for example in the form of starch esters with a level ofsubstitution of between 0.2 and 2.5, starch hydroxypropylate, or starchmodified with fatty chains.

By destructured starch reference is made here to the teachings includedin patents EP-0 118 240 and EP-0 327 505, this being understood to meanstarch processed in such a way that it does not have the so-called“Maltese crosses” under the optical microscope in polarised light andthe so-called “ghosts” under a phase contrast microscope.

Advantageously the starch is destructured by means of a process ofextrusion at temperatures of between 110 and 250° C., preferably between130° C. and 180° C., preferably at pressures between 0.1 and 7 MPa,preferably 0.3-6 MPa, preferably providing a specific energy of morethan 0.1 kWh/kg during that extrusion.

Destructuring of the starch preferably takes place in the presence of1-40% by weight with respect to the weight of the starch of one or moreplasticisers selected from water and polyols having 2 to 22 carbonatoms. As far as the water is concerned, this may be water whichincludes that naturally present in the starch. Among the polyols,polyols having from 1 to 20 hydroxyl groups containing 2 to 6 carbonatoms, their ethers, thioethers and organic and inorganic esters arepreferred. Examples of polyols are glycerine, diglycerol, polyglycerol,pentaerythritol, polyglycerol ethoxylate, ethylene glycol, polyethyleneglycol, 1,2-propandiol, 1,3-propandiol, 1,4-butandiol, neopentylglycol,sorbitol monoacetate, sorbitol diacetate, sorbitol monoethoxylate,sorbitol diethoxylate, and mixtures thereof. In a preferred embodimentthe starch is destructured in the presence of glycerol or a mixture ofplasticisers comprising glycerol, more preferably comprising between 2and 90% by weight of glycerol. Preferably the destructured orcross-linked starch according to this invention comprises between 1 and40% by weight of plasticisers with respect to the weight of the starch.

When present, the starch in the composition is preferably present in theform of particles having a circular or elliptical cross-section or inany event a cross-section similar to an ellipse having an arithmeticmean diameter measured taking the major axis of the particle intoconsideration which is of mean diameter less than 1 micron and morepreferably less than 0.5 μm.

In a preferred embodiment of this invention, the filler agent is amineral filler, more preferably is talc, present in the form ofparticles having a median diameter of less than 3 microns, preferably ofless than 2.5 microns, more preferably of less than 2 microns, whereinthe particle size distribution is measured by Sedigraph according to ISO13317-3. It has in fact been discovered that the filler agents of thetype described above characterised by the said median diameter improvedisintegratability properties as well as the heat resistance and themechanical properties. Preferably, the thermoformed articles arecharacterised by G′ modulus values, obtained at 70° C. through dynamicmechanical-torsional analysis (DMTA), higher than 180, preferably higherthan 230 MPa, and G′ modulus values, obtained at 90° C. through DMTA,higher than 125, preferably higher than 150 MPa.

Without being bound thereby to any specific theory, it is felt that thesaid filler agents, when used in the compositions according to theinvention, become stratified and agglomerate during the moulding stage,thus slowing the action of the agents responsible for the disintegrationof the thermoformed articles.

In addition to components i.-iv. the composition according to thisinvention preferably also contains at least one other component selectedfrom the group consisting of cross-linking agent and/or chain extender,plasticisers, UV stabilisers, lubricants, nucleating agents,surfactants, antistatic agents, pigments, flame retardants,compatibilising agents, lignin, organic acids, antioxidants, mouldprevention agents, waxes, process coadjuvants and polymer componentspreferably selected from the group consisting of vinyl polymers,polyesters of diacid diols which are other than polyester i.,polyamides, polyurethanes, polyethers, polyureas and polycarbonates.

The cross-linking agents and/or chain extender are selected fromcompounds having di- and/or multiple functional groups incorporatingisocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxy,anhydride or divinyl ether groups and mixtures thereof.

Preferably the cross-linking agent and/or chain extender comprises atleast one compound having di- and/or multiple functional groupscomprising isocyanate groups. More preferably, the cross-linking agentand/or chain extender comprises at least 25% by weight of one or morecompounds having di- and/or multiple functional groups incorporatingisocyanate groups. Particularly preferred are mixtures of compoundshaving di- and/or multiple functional groups incorporating isocyanategroups with compounds having di- and/or multiple functional groupsincorporating epoxy groups, even more preferably comprising at least 75%by weight of compounds having di- and/or multiple functional groupsincorporating isocyanate groups.

The compounds having di- and multiple functional groups incorporatingisocyanate groups are preferably selected from p-phenylene diisocyanate,2,4-toluene diisocyanate, 2,6-toluene diisocyanate,4,4-diphenylmethane-diisocyanate, 1,3-phenylene-4-chloro diisocyanate,1,5-naphthalene diisocyanate, 4,4-diphenylene diisocyanate,3,3′-dimethyl-4,4diphenylmethane diisocyanate,3-methyl-4,4′-diphenylmethane diisocyanate, diphenylester diisocyanate,2,4-cyclohexane diisocyanate, 2,3-cyclohexane diisocyanate, 1-methyl2,4-cyclohexyl diisocyanate, 1-methyl 2,6-cyclohexyl diisocyanate,bis-(isocyanate cyclohexyl) methane, 2,4,6-toluene triisocyanate,2,4,4-diphenylether triisocyanate,polymethylene-polyphenyl-polyisocyanates, methylene diphenyldiisocyanate, triphenylmethane triisocyanate,3,3′ditolylene-4,4-diisocyanate, 4,4′-methylenebis (2-methyl-phenylisocyanate), hexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate,1,2-cyclohexylene diisocyanate and their mixtures. In a preferredembodiment, the compound comprising isocyanate groups is4,4-diphenylmethane-diisocyanate.

With regard to compounds having di- and multiple functional groupsincorporating peroxide groups, these are preferably selected frombenzoyl peroxide, lauroyl peroxide, isononanoyl peroxide,di-(t-butylperoxyisopropyl)benzene, t-butyl peroxide, dicumyl peroxide,alpha,alpha′-di(t-butylperoxy)diisopropylbenzene,2,5-dimethyl-2,5di(t-butylperoxy)hexane, t-butyl cumyl peroxide,di-t-butylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne,di(4-t-butylcyclohexyl)peroxy dicarbonate, dicetyl peroxydicarbonate,dimyristyl peroxydicarbonate,3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, di(2-ethylhexyl)peroxydicarbonate and their mixtures.

Examples of compounds having di- and multiple functional groupsincorporating epoxy groups which may advantageously be used in thecomposition according to this invention are all the polyepoxides fromepoxydised oils and/or styrene-glycidylether-methylmethacrylate,glycidylether methylmethacrylate, included in a range of molecularweights between 1000 and 10000 and having an epoxy number per moleculein the range from 1 to 30 and preferably between 5 and 25, and theepoxides selected from the group comprising: diethylene glycoldiglycidylether, polyethylene glycol diglycidyl ether, glycerolpolyglycidyl ether, diglycerol polyglycidyl ether, 1,2-epoxybutane,polyglycerol polyglycidyl ether, isoprene diepoxy and cycloaliphaticdiepoxides, 1,4-cyclohexandimethanol diglycidyl ether, glycidyl2-methylphenyl ether, glycerol propoxylatotriglycidyl ether,1,4-butandiol diglycidyl ether, sorbitol polyglycidyl ether, glyceroldiglycidyl ether, tetraglycidyl ether of meta-xylenediamine and thediglycidyl ether of bisphenol A and their mixtures.

Together with the compounds having di- and multiple functional groupsincorporating isocyanate, peroxide, carbodiimide, isocyanurate,oxazoline, epoxy, anhydride and divinylether groups of the compositionaccording to this invention, catalysts may be also used to increase thereactivity of the reactive groups. In the case of polyepoxides, salts offatty acids, even more preferably calcium and zinc stearates, arepreferably used.

In a particularly preferred embodiment of the invention thecross-linking agent and/or chain extender of the composition comprisescompounds incorporating isocyanate groups, preferably4,4-diphenylmethane-diisocyanate, and/or incorporating carbodiimidegroups, and/or incorporating epoxy groups, preferably of thestyrene-glycidylether-methylmethacrylate type.

With regard to plasticisers, in addition to the plasticisers preferablyused for the preparation of destructured starch described above thereare preferably present in the composition according to this inventionone or more plasticisers selected from the group comprising phthalates,such as for example diisononyl phthalate, trimellitates, such as forexample the esters of trimellitic acid with C₄-C₂₀ monoalcoholspreferably selected from the group comprising n-octanol and n-decanol,and aliphatic esters having the following structure:R₁—O—C(O)—R₄—C(O)—[—O—R₂—O—C(O)—R₅—C(O)—]_(m)—O—R₃in which:

-   R₁ is selected from one or more of the groups comprising H, linear    and branched saturated and unsaturated alkyl residues of the C₁-C₂₄    type, polyol residues esterified with C₁-C₂₄ monocarboxylic acids;-   R₂ comprises —CH₂—C(CH₃)₂—CH₂— and alkylene C₂-C₈, groups and    comprises at least 50% in moles of the said —CH₂—C(CH₃)₂—CH₂—    groups;-   R₃ is selected from one or more of the groups comprising H, linear    and branched saturated and unsaturated alkyl residues of the C₁-C₂₄    type, polyol residues esterified with C₁-C₂₄ monocarboxylic acids;-   R₄ and R₅ are the same or different, comprise one or more C₂-C₂₂,    preferably C₂-C₁₁, more preferably C₄-C₉ alkylenes and comprise at    least 50% in moles of C₇ alkylenes.

m is a number between 1 and 20, preferably 2-10, more preferably 3-7.

Preferably, in the said esters at least one of the R₁ and/or R₃ groupscomprises, preferably in quantities ≥10% in moles, more preferably ≥20%,even more preferably ≥25% in moles with respect to the total quantitiesof R₁ and/or R₃ groups, polyol residues esterified with at least oneC₁-C₂₄ monocarboxylic acid selected from the group comprising stearicacid, palmitic acid, 9-ketostearic acid, 10-ketostearic acid andmixtures thereof. Examples of aliphatic esters of this type aredescribed in Italian patent application MI2014A000030 and PCTapplications PCT/EP2015/050336, PCT/EP2015/050338.

When present, the selected plasticisers are preferably present up to 10%by weight, with respect to the total weight of the composition.

The lubricants are preferably selected from esters and metal salts offatty acids such as for example zinc stearate, calcium stearate,aluminium stearate and acetyl stearate. Preferably the compositionaccording to this invention comprises up to 1% by weight of lubricants,more preferably up to 0.5% by weight, with respect to the total weightof the composition.

Examples of nucleating agents include the sodium salt of saccharine,calcium silicate, sodium benzoate, calcium titanate, boron nitride,isotactic polypropylene, low molecular weight PLA. These additives arepreferably added in quantities up to 10% by weight and more preferablybetween 2 and 6% by weight with respect to the total weight of thecomposition.

Pigments may also be added if necessary, for example titanium dioxide,clays, copper phthalocyanin, titanium dioxide, silicates, oxides andhydroxides of iron, carbon black and magnesium oxide. These additiveswill preferably be added up to 10% by weight.

Among the vinyl polymers, those preferred are: polyethylene,polypropylene, their copolymers, polyvinyl alcohol, polyvinyl acetate,polyethyl vinyl acetate and polyethylene vinyl alcohol, polystyrene,chlorinated vinyl polymers, polyacrylates.

Among the chlorinated vinyl polymers these are here intended to includein addition to polyvinyl chloride: polyvinylidene chloride, polyethylenechloride, poly(vinyl chloride-vinyl acetate), poly(vinylchloride-ethylene), poly(vinyl chloride-propylene), poly(vinylchloride-styrene), poly(vinyl chloride-isobutylene) and copolymers inwhich polyvinyl chloride represents more than 50% in moles. The saidcopolymers may be random, block or alternating.

With regard to the polyamides of the composition according to thisinvention, these are preferably selected from the group consisting ofpolyamide 6 and 6,6, polyamide 9 and 9,9, polyamide 10 and 10,10,polyamide 11 and 11,11, polyamide 12 and 12,12 and their combinations ofthe 6/9, 6/10, 6/11, 6/12 type, their mixtures and both random and blockcopolymers.

Preferably the polycarbonates of the composition according to thisinvention are selected from the group comprising polyalkylenecarbonates, more preferably polyethylene carbonates, polypropylenecarbonates, polybutylene carbonates, their mixtures and copolymers bothrandom and block copolymers.

Among the polyethers, those preferred are those selected from the groupconsisting of polyethylene glycols, polypropylene glycols, polybutyleneglycols their copolymers and their mixtures with molecular weights from70,000 to 500,000.

With regard to polyesters of diacid diols which are other than polyesteri., these preferably comprise:

-   -   a) a dicarboxylic component comprising, with respect to the        total dicarboxylic component:        -   a1) 20-100% in moles of units deriving from at least one            aromatic dicarboxylic acid,        -   a2) 0-80% in moles of units deriving from at least one            saturated aliphatic dicarboxylic acid,        -   a3) 0-5% in moles of units deriving from at least one            unsaturated aliphatic dicarboxylic acid;    -   b) a diol component comprising, with respect to the total diol        component:        -   b1) 95-100% in moles of units deriving from at least one            saturated aliphatic diol;        -   b2) 0-5% in moles of units deriving from at least one            unsaturated aliphatic diol.

Preferably the aromatic dicarboxylic acids, saturated aliphaticdicarboxylic acids, unsaturated aliphatic dicarboxylic acids, saturatedaliphatic diols and unsaturated aliphatic diols for the said polyestersare selected from those described above for the polyester (component i.)of the composition according to this invention.

More preferably the said diacid-diol polyesters which are other thanpolyester i. are selected from the group consisting of poly(ethyleneterephthalate), poly(propylene terephthalate), poly(butyleneterephthalate), poly(ethylene 2,5furandicarboxylate), poly(propylene2,5-furandicarboxylate), poly(butylene 2,5-furandicarboxylate) and blockor random copolymers of the poly(alkylene2,5-furandicarboxylate-co-alkylene terephthalate) type.

The process of production of the polymer composition according to thisinvention can be carried out by any of the processes known in the art.Advantageously the polymer composition according to this invention isproduced by means of extrusion processes in which the polymer componentsare mixed in the fused state. In extruding the composition thecomponents may be fed all together or one or more of them may be fedseparately along the extruder.

This invention also relates to thermoformed articles, comprising thesaid polymer composition, which in fact has processability andperformance in use properties which render it particularly suitable forthis use. Its properties in fact make it possible to manufacturethermoformed articles having good resistance to deformation, highdimensional stability and bend temperature under load properties whichare able to disintegrate and biodegrade in industrial compostingprocesses. Preferably, thermoformed articles, comprising the compositionaccording to this invention, are biodegradable according to EN 13432,when having thickness up to 250 μm.

For example the polymer composition according to the invention isparticularly suitable for the manufacture thermoformed articles such asfor example, plates and cups, rigid containers, capsules for thedispensing of beverages, preferably hot beverages, lids and covers, andfood packaging which can be heated in conventional and microwave ovens.

The composition according to this invention and the thermoformedarticles it comprises are preferably characterised by a THF content ofbelow 10 mg/kg, preferably <5 mg/kg, and are capable of being used incontact with food, as occurs for example in the case of capsules for thedispensing of beverages.

In a preferred embodiment, this invention relates to a capsule for thedispensing of beverages characterised by a THF content of below 3 mg/kg,preferably 1 mg/kg. In the case of the compositions which comprisepolyesters comprising 1,4-butylene dicarboxylate units as component i.the said low THF content can be obtained by subjecting the compositionsaccording to this invention, or the thermoformed articles comprisingthem, to at least one stage of volatilisation of the THF.

In a preferred embodiment of this invention the said thermoformedarticles comprise at least one layer A comprising the compositionaccording to this invention and at least one layer B comprising at leastone polymer selected from the group comprising diacid-diol polyestersand hydroxy acid polyesters, and are preferably characterised by amutual arrangement of the said layers A and B selected from A/B, A/B/Aand B/A/B. In a further particularly preferred embodiment the said layerB consists of a polyester of lactic acid.

As far as the process of moulding by means of thermoforming isconcerned, the polymer composition according to this invention may bethermoformed by means of methods known to those skilled in the art, fromfor example from sheets or film, under pressure or under vacuum. Thisinvention also relates to the said sheets or film comprising thecomposition according to this invention, used for the production ofmoulded articles by means of thermoforming.

Typical operating conditions for thermoforming provide for example atime of 5-8 seconds for heating the said sheets or film until theysoften, and moulding times of between 15 and 20 seconds.

The invention will now be illustrated through a number embodiments whichare intended to be by way of example and do not limit the scope ofprotection of this patent application.

EXAMPLES

Component i

-   i-1=Poly(1,4-butylene succinate) (“PBS”) prepared according to the    following method: 17150 g of succinic acid, 14000 g of    1,4-butandiol, 26.75 g of glycerine and 2.0 g of an 80% by weight    ethanolic solution of diisopropyl triethanolamine titanate (Tyzor    TE, containing 8.2% by weight of titanium) were added to a steel    reactor having a geometrical capacity of 40 litres fitted with a    mechanical stirring system, an inlet for nitrogen, a distillation    column, a knock-down system for high boiling point components and a    connection to a high vacuum system in a diol/dicarboxylic acid (MGR)    molar ratio of 1.08. The temperature of the mass was gradually    raised to 230° C. over a period of 120 minutes. When 95% of the    theoretical water has been distilled off, 21.25 g of tetra n-butyl    titanate (corresponding to 119 ppm of metal with respect to the    quantities of poly1,4-butylene succinate that would be theorically    obtainable by converting all the succinic acid fed to the reactor)    were added. The temperature of the reactor was then raised to    235-240° C. and the pressure was gradually reduced to a value below    2 mbar over a period of 60 minutes. The reaction was allowed to    proceed for the time required to obtain a poly(1,4-1,4-butylene    succinate) with an MFR of approximately 7 (g/10 minutes at 190° C.    and 2.16 kg), and the material was then discharged in the form of a    filament into a water bath and granulated.

i-2=Poly(1,4-butylene sebacate-co-1,4-butylene terephthalate) (“PBST”)was prepared according to the following method: 8160 g of terephthalicacid, 11198 g of sebacic acid, 11296 g of 1,4-butanediol, 14.4 g ofglycerine and 2.0 g of an 80% by weight ethanolic solution ofdiisopropyl triethanolamine titanate (Tyzor TE, containing 8.2% byweight of Titanium) were added in a diol/dicarboxylic acid molar ratio(MGR) of 1.20 to a steel reactor having a geometrical capacity of 40litres, fitted with a mechanical stirrer system, an inlet for nitrogen,a distillation column, a knock-down system for high-volume distillatesand a connection to a high vacuum system. The temperature of the masswas gradually increased to 230° C. over a period of 120 minutes. When95% of the theoretical water had been distilled off, 21.2 g(corresponding to 119 ppm of metal with respect to the quantity of PBSTwhich could theoretically be obtained by converting all the sebacic acidand all the terephthalic acid fed to the reactor) of tetra n-butylTitanate was added. The temperature of the reactor was then raised to235-240° C. and the pressure was gradually reduced until a value of lessthan 2 mbar was reached over a period of 60 minutes. The reaction wasallowed to proceed for the time required to obtain a poly(1,4-butylenesebacate-co-1,4-butylene terephthalate) with an MFR of approximately 5(g/10 minutes at 190° C. and 2.16 kg), and the material was thendischarged in the form of a filament into a water bath and granulated.

Component ii

-   ii=Ingeo 4043D polylactic acid (“PLA”), MFR 3.5/10 min (at 190° C.,    2.16 kg).    Component iii-   iii=HMV-15CA Carbodilite from Nisshinbo Chemical Inc.    Component iv-   iv=micronised talc having a median diameter of 1.9 microns (particle    size distribution by Sedigraph according to ISO 13317-3), Mistron    R10C commercial grade from Imerys.

Examples 1-3—Production of Thermoformed Articles Comprising theComposition According to this Invention

TABLE 1 Compositions in Examples 1-3. Components (% wt) Example i-1 i-2ii iii iv 1 47.7 — 16 0.2 36.1 2 44.7 3 16 0.2 36.1 3 42.7 5 16 0.2 36.1

The composition in Table 1 was fed to an Icma San Giorgio MCM 25 HTmodel co-rotating twin screw extruder under the following operatingconditions:

Screw diameter (D)=25 mm;

L/D=52;

Rotation speed=200 rpm;

Temperature profile=100-180-215×9-180-170-160° C.;

Throughput 10.1 kg/h;

Degassing under vacuum;

The granules were fed to a Curti single-screw extruder (screw diameter40 mm—L/D 25) equipped with a flat head 400 mm wide and Teknomastcompound rolling unit of 3 rolls of width 400 and diameter 200—andprovided with water cooling. The operating conditions were as follows:

Screw diameter (D)=40 mm;

L/D=25;

Rotation speed=60 rpm;

Temperature profile=Extruder: 190-5×200° C./Head: 6×200° C.;

Throughput 20 kg/h.

From the sheets were obtained bars (length 30 mm, width 6 mm, thickness0.5 mm) which then underwent dynamic mechanical-torsional analysis(DMTA) in torsional mode using an Ares G2 rotational rheometer from TAInstrument. The samples were heated from 30° C. to 120° C. at 3° C./minimposing a deformation of 0.1% and a frequency of 1 Hz.

Heat deflection temperature (HDT) was measured according to standardASTM-D648 using a 0.455 MPa load (Method B), on moulded test specimensof the “bar” type (length 127 mm, width 12.7 mm, thickness 3.2 mm) usingCeast 6510 Test-A-Matic model equipment. HDT values were determined intriplicate for each composition. The value stated corresponds to thearithmetic mean of the measured values.

Sheets of 350 μm thickness were thermoformed on an Artpack thermoformingmachine in a single die mould for the production of plates (diameter 220mm, depth 40 mm) using the following thermoforming operating conditions:

-   -   Heating by means of 15 IR lamps (rated maximum power of each        lamp 325W);    -   Heating time 5-8 sec. (to softening);    -   Total cycle time 15-20 sec.

The plates obtained underwent a disintegration test in controlledcomposting according to standard IS020200:2004, showing a weight loss ofmore than 90% over 90 days at 58° C.

TABLE 2 HDT and DMTA characterization. G’ [MPa] a G’ [MPa] a Example HDT° C. T = 70° C. T = 90° C. 1 91 ± 1 340 232 2 82 ± 1 309 202 3 82 ± 1271 176

The invention claimed is:
 1. A polymer composition for the production ofthermoformed articles comprising, with respect to the sum of componentsi.-iv.: i) 20-60% by weight of at least one polyester i. comprising: a)a dicarboxylic component comprising with respect to the totaldicarboxylic component: a1) 95-100% in moles of units deriving fromsuccinic acid, a2) 0-5% in moles of units deriving from at least oneunsaturated aliphatic dicarboxylic acid; b) a diol component comprising,with respect to the total diol component,: b1) 95-100% in moles of unitsderiving from at least one saturated aliphatic diol; b2) 0-5% in molesof units deriving from at least one unsaturated aliphatic diol; ii)5-35% by weight of at least one polyhydroxyalkanoate ii.; iii) 0.01-5%by weight of at least one hydrolysis stabilizer comprising at least onecompound having di- and/or multiple functional groups comprisingcarbodiimide groups; iv) 5-50% by weight of at least one filler agent.2. The polymer composition according to claim 1, wherein the saidaliphatic polyester (AP) is poly(1,4-butylene succinate).
 3. The polymercomposition according to claim 1, wherein the said at least onepolyhydroxyalkanoate ii. is selected from the group consisting ofpolyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate,polyhydroxybutyrate-valerate, polyhydroxybutyrate propanoate,polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate,polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate,polyhydroxybutyrate-ottadecanoate, and poly-3-hydroxybutyrate4-hydroxybutyrate.
 4. The polymer composition according to claim 1,wherein the said at least one compound having di- and multiplefunctional groups incorporating carbodiimide groups which are used inthe hydrolysis stabilizer iii. is selected from poly(cyclooctylenecarbodiimide), poly(1,4-dimethylenecyclohexylene carbodiimide),poly(dicyclohexylmethane carbodiimide), poly(cyclohexylenecarbodiimide), poly(ethylene carbodiimide), poly(butylene carbodiimide),poly(isobutylene carbodiimide), poly(nonylene carbodiimide),poly(dodecylene carbodiimide), poly(neopentylene carbodiimide),poly(1,4-dimethylene phenylene carbodiimide),poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide),poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide), poly(2,6diisopropyl-1,3-phenylene carbodiimide), poly (tolyl carbodiimide),poly(4,4′-diphenylmethane carbodiimide),poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylene carbodiimide),poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylenecarbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide),p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide),1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylenebis(ethylcarbodiimide) and their mixtures.
 5. The polymer compositionaccording to claim 1, wherein the said at least one filler agent iv. isa mineral filler.
 6. The polymer composition according to claim 5,wherein the said at least one filler agent iv. is talc.
 7. The polymercomposition according to claim 5, wherein the said talc is present inthe form of particles having a median diameter of less than 3 microns.8. The polymer composition according to claim 5, wherein the said talcis present in the form of particles having a median diameter of lessthan 2.5 microns.
 9. The polymer composition according to claim 5,wherein the said talc is present in the form of particles having amedian diameter of less 2 microns.
 10. A thermoformed article comprisingthe polymer composition according to claim
 1. 11. The thermoformedarticle according to claim 10, selected from the group consisting of,plates, cups, rigid containers, capsules for the dispensing ofbeverages, lids, covers, or containers for food which can be heated inconventional or microwave ovens.
 12. The polymer composition accordingto claim 4, wherein the said aliphatic polyester (AP) ispoly(1,4-butylene succinate).
 13. The polymer composition according toclaim 4, wherein the said at least one polyhydroxyalkanoate ii. isselected from the group consisting of polyesters of lactic acid,poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate,polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate,polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate,polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, andpoly-3-hydroxybutyrate 4-hydroxybutyrate.
 14. The polymer compositionaccording to claim 2, wherein the said at least one polyhydroxyalkanoateii. is selected from the group consisting of polyesters of lactic acid,poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate,polyhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate,polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate,polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, andpoly-3-hydroxybutyrate 4-hydroxybutyrate.
 15. The polymer compositionaccording to claim 5, wherein the said at least one compound having di-and multiple functional groups incorporating carbodiimide groups whichare used in the hydrolysis stabilizer iii. is selected frompoly(cyclooctylene carbodiimide), poly(1,4-dimethylenecyclohexylenecarbodiimide), poly(dicyclohexylmethane carbodiimide),poly(cyclohexylene carbodiimide), poly(ethylene carbodiimide),poly(butylene carbodiimide), poly(isobutylene carbodiimide),poly(nonylene carbodiimide), poly(dodecylene carbodiimide),poly(neopentylene carbodiimide), poly(1,4-dimethylene phenylenecarbodiimide), poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide),poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide), poly(2,6diisopropyl-1,3-phenylene carbodiimide), poly (tolyl carbodiimide),poly(4,4′-diphenylmethane carbodiimide),poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylene carbodiimide),poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylenecarbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide),p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide),1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylenebis(ethylcarbodiimide) and their mixtures.
 16. The polymer compositionaccording to claim 2, wherein the said at least one compound having di-and multiple functional groups incorporating carbodiimide groups whichare used in the hydrolysis stabilizer iii. is selected frompoly(cyclooctylene carbodiimide), poly(1,4-dimethylenecyclohexylenecarbodiimide), poly(dicyclohexylmethane carbodiimide),poly(cyclohexylene carbodiimide), poly(ethylene carbodiimide),poly(butylene carbodiimide), poly(isobutylene carbodiimide),poly(nonylene carbodiimide), poly(dodecylene carbodiimide),poly(neopentylene carbodiimide), poly(1,4-dimethylene phenylenecarbodiimide), poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide),poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide), poly(2,6diisopropyl-1,3-phenylene carbodiimide), poly (tolyl carbodiimide),poly(4,4′-diphenylmethane carbodiimide),poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylene carbodiimide),poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylenecarbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide),p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide),1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylenebis(ethylcarbodiimide) and their mixtures.
 17. The polymer compositionaccording to claim 3, wherein the said at least one compound having di-and multiple functional groups incorporating carbodiimide groups whichare used in the hydrolysis stabilizer iii. is selected frompoly(cyclooctylene carbodiimide), poly(1,4-dimethylenecyclohexylenecarbodiimide), poly(dicyclohexylmethane carbodiimide),poly(cyclohexylene carbodiimide), poly(ethylene carbodiimide),poly(butylene carbodiimide), poly(isobutylene carbodiimide),poly(nonylene carbodiimide), poly(dodecylene carbodiimide),poly(neopentylene carbodiimide), poly(1,4-dimethylene phenylenecarbodiimide), poly(2,2′,6,6′-tetraisopropyldiphenylene carbodiimide),poly(2,4,6-triisolpropyl-1,3-phenylene carbodiimide), poly(2,6diisopropyl-1,3-phenylene carbodiimide), poly (tolyl carbodiimide),poly(4,4′-diphenylmethane carbodiimide),poly(3,3′-dimethyl-4,4′-biphenylene carbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylene carbodiimide),poly(3,3′-dimethyl-4,4′-diphenylmethane carbodiimide), poly(naphthylenecarbodiimide), poly(isophorone carbodiimide), poly(cumene carbodiimide),p-phenylene bis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylene bis(ethylcarbodiimide),1,10-decamethylene bis(ethylcarbodiimide), 1,12 dodecamethylenebis(ethylcarbodiimide) and their mixtures.
 18. The polymer compositionaccording to claim 3, wherein the said at least one filler agent iv. isa mineral filler.
 19. The polymer composition according to claim 2,wherein the said at least one filler agent iv. is a mineral filler. 20.The polymer composition according to claim 4, wherein the aliphaticpolyester (AP) is poly(1,4-butylene succinate), the at least onepolyhydroxyalkanoate ii. is a polyester of lactic acid containing atleast 95% by weight of repetitive units deriving from L-lactic orD-lactic acid or their combinations, with a molecular weight Mw of morethan 50,000 and with a shear viscosity of between 50 and 500 Pa·s; andthe at least one filler agent iv. is talc in the form of particleshaving a median diameter of less than 2 microns.